Recovering gasoline



' 1,613 los Jan 4 1927" F. E. HosMER RE'COVERING GASOLINE Filed July 16,1926 RES/DUAL EOLD GA '4. 6A: t, A QAW Q E' l H i mw E 3 COOLER MIPCawxnam MN PRAY 'l cHAMc/e S ik 3 F/RJT #C0/VD PRECOOLER PRECQOLERSWW/nto@ fedEIYosmer Patented Jan. 4, 1927.

UNIT'EDSTATES' PATr-:NT oFFlcE".

mi) E. HOSIIIEB, F FORT WORTH, TEXAS.

ncovnnme GASOLINE.

almacenan mea July 1s, 1926. serial No. 122,927

This invention relates to processes of re? covering gasoline, and moreespecially to a method of recovering gasollne from cas# inghead ornatural gas-by coolingvand re-.,

frigeration wherein higher boiling fractions contained in-:casinghead ornatural gas are condensed and separated from the lower boilingfractions;and it comprises la.tproc' 'ess wherein-natural -or casingheadgas isfirst contacted =in the gaseous 'state with cobling liquids previouslycooledby con-v tact with cold gas subsequently formed fm;

4the process and the then -precooled gas. brought into intimate contact-1n a suitablechamber with liquefied lower boiling' frac-4 tionsfofthejcasmghead gas, whereby the that is, agasoline containing veryvolatile` components which must ,be weathered out.'

liquefied lower boiling fractions are caused to evaporate in such amanner that theI gas undergoing treatment is-further chilled fand thedesired higherI boiling fraction-s liquefied and separated from thegases in contact therewith, and the 'said gases 'conducted back into thecooling medium yto chill the same; it further comprises liquefying apart of these cooling gases for the purposes of refrigeratingthe/incoming natural gas it further comprises a new method of chillingvapors containing gasoline for the purpose of liquefying the gasoline bycontacting said vaporswith a suitable cooling medium;

and it further comprises as a new organiv` zation of apparatus elements-aF heat eX- changer particularly adapted to precool gasoline vaporsprior to the liquefaction of thev desirable constituents thereof; all asmore fully-hereinafter set forth andas claimed. u

In the recovery of gasoline from natural gasr and casingheal gas, awidevarietybf processes have been proposed and are in use, utilizingpressure, chilling` andi-scrubbing in various ways.V 4All. theseprocesses, produce what is known as a wild gasoline,

rin making commercial gasoline. In weathering, however, there isffa lossotV desir; able, less volatile products which ,accom- A pany vapors ofthe very volatile components; It is the object of thepresent'.-invention to produce in "a simple way a gasoline lrequiringless weathering; and to accomplish this with a minimum plant equipment.A

lVet natural as' contains in addition toA methane and et ane, which arepermanentgases for the present.purposes,y awide va-rifl ety of vapors'ofcondensible'hydrocarbons;

Inthe present invention, natural gas coming'ffrom any suitablesource isusually,- but not always, putl under some ,degree of pressure bympump ifthe line pressure be deemed not suiiicient., I n this stage of oper-lation, the gas may, indeed, be .atordinary or atmospheric pressure,although I find it bet;

ter to work under at least a 4few pounds ex# l tra pressure. Aftercompression, the gas is cooled in an ordinary way. Any condensate whichmay be producedfat this point is re-v moved from the system. The gas isnowfurther cooled in a novel type lof precooler by bringing the gas intocontact rwith a li'luid cooling medlum such as calci'um chlo'. r1

e solution, or suitable solution lwhich will not freeze at temperaturesused, which cooling medium has been v'cooled to a suffi.- ciently lowtemperature by cold duced further along' in the'process'.

`After -the tem erature of the raw gas has. been lowere to. between 0 F.and- -50 F. by contact with cold calcium chloride solution it .is thenpassed into intimate contact with: liquid. gasoline which gasoline l-hasbeen chilled to about -7 0 F. or lower by cold-gas'als'o subsequentlyproduced, the

.temperatures depending upon requirements.

After the rawfgashas been precooled byv these two cooling mediums, it isthen conducted into. a spray -chamberwherein it is brought into contactwith a quantity of liquefiedlower boiling fractions ofthe naturalgasbbtained. in the process -in aflater sta-ge. These lower boilingfractions under# go self-evaporation 4while in contact with the,A rawgas, 'w1th thexresultthat the tem? pera-ture of the rawgas is loweredto' sucli an extent that the desired higher boiling fractions areliquefied.` These higher Boilfractions are then separated frometheresidual' gas. Alflheresidua'l gas whichhas a verylow temperature,vwhich maybe about ,'"0 F., conducted into contactwith the gasolinepreviously mentioned as a cooling medium for the incoming raw gasthereby lowering the temperature of the gasoline. The residual gas isthen conducted into contact with the calcium chloride solution used v toprecool the gas in the first precooler stage.

vshown more or less diagrammaticall After having fulfilled its functionof cooling the calcium chloride solution the now somewhat warmedresidual gas is conducted out of the system, a part thereof howeverbeing recompressed and chilled and the liquefied portions thereofconducted back into the system, brought into contact with incomingprecooled raw gas, permitted to undergo self-evaporation, the raw gasthus cooled to a condensing temperature, and the cycle re eated.

n the accompanying illustration I have certain embodiments of myinvention. n this showing, l

Figure 1 is a flow sheet diagram indicating the course of the raw gasand the cooling medium in the system; and i Figure 2 shows in detaillthe construction of the heat exchanger.

Referring more particularly to Figure 1, raw gas enters the system at 1,and is compressed in compressor C which may be of ordinary construction.If the gas is already under a suitable pressure it need not becompressed at this stage. If it is not, the compressed gas is cooled byan ordinary water cooling device A whereby the heat of compression isextracted from il'. Leaving A the as is conducted to drip tank whereinsuc constituents as have l`quecd are separated and withdrawn from thesystem.

The gas leaving B is conducted through line- 2 to the lower part of thefirst precooler lil wherein it is brought into contact with `acountercurrent shower of-a chilled liquid coolingv medium such ascalcium chloride solution. Passing from E the gas is conducted throughline 3 into the second precooler H wherein -the gas passes upwardthrough a downcomingshower of extremely v cold gasoline. The gas nowvery much low ered 1n temperature passesfby means of line 4 into thespray chamber S wherein it is brought into contact with low boilingliquids undergoing self-evaporation. From the spray chamber the gaseousmixture passes by line 5 into a secondaccumulator tank W in which theliquefied port-ion of the gaseous mixture is separated from the residualgas and conducted to a lsuitable storage tank (not shown) by line 6. Theresidual gas leaving the top of lV by line 7 is conducted back to thesecond precooler H wherein itis brought into contact with gasoline inorder to chill the same and make it suitable as a cooling medium for theraw gas.

The precooler H (see Figure 2) is constructed in the form of a tankdivided at its mid portion by partition 30 thereby separating completelythe upper half vof the tank from the lower. The lower half of the tank35 is provided with an outlet 36 leading to a pump 37 (showndiagrammatically) which pumps the cooling medium, in this case gasoline,into the upper half of the precooler designated as 40. The coolingmedium is conducted into the upper half of the precooler 40 by line 38which terminates within the precooler portion 40 and at the top thereofin a spray device of ordinary construction 39. The upper half of theprecooler 40, is provded at its lower extremity with an outlet 41connected with a liquid seal 42. The other end of the liquid seal passesinto (the lower half of the precooler 35` at the upper extremity thereofby line 43 and terminates in a spray device 44. 'lhe raw gas enteringthev precooler H by line 3 is sprayed upwardly into cont-act with tiedowncommggasoline from 44 by spray device 45. The operaton of the secondprecooler H is as follows: Cold gas leaving the accumulator tank W isconducted by linei into the upper half 40 of the precooler and sprayedupwardly by spray device 46. This cold gas meets a downcoming stream ofgasoline cominor from 39 and cools the same. The now chilled gasolinepassesby 41 through the liquid seal 42 and into the lower half 35 of theprecooler, is sprayed by means of 44 into the upcoming stream of rawgas, thereby cooling the same. 'llie coolng medium is withdrawn from thelower half 35 of the cooler and pumped by pump 87 back into the upperhalf 40 wherein it is once more cooled for reuse by incoming cold gasfrom the accumulator tank W. The cold gas which has sufiiced to chillthe coolingr medium, gasoline, withdrawn from the upper half 40 of theprecooler H and is conducted by line 8 into the lire-tv precooler.wherein calcium chloride solution or some non-freezing medium is usedas the cooling medium.

The first precooler l] is identical in its structural features with the.precooler H, it being provided with spray devices 47, 48, 49 and 50,and liquid seal 51 and a. pump 52,

and is also divided at its mid portion by a.

` which is a few degrees below 0 F. is sprayed upwardly through 47 intoa downcoming stream of calcium chloride from 48 whereby the calciumchloride solution is chilled to a temperature between 0"y F. and 50 F,The now cooled calcium chloride solution is conducted into the lowerhalf 54 of the precooler through liquid seal 51 and spray device 49 andthen acts to cool incoming raw gas from line 2 and spray device 50. Thecalcium chloride solution after it has adsorbed heat from the raw gas isthen pumped by 52 through line 55 .back into the upper half 56 of theprccooler where it is again brought into contact with further quantitiesof cold gas and is again chilled. The cold gas, which consists of mostofthe lower boiling fractions in the natural or casingl head gas, afterit has acted to lower the temperatures of the calcium chloride solutionis conducted out of the upper half 56 ofthe precooler Ebylinc 9 to astorage tank (not shown)'.l A part, however, of this gas is passed byline 10 (Fig. 1) into a compressor D wherein it is compressed and'subsequently cooled in a Watercooler R and then passed to an accumulatortank J. The liquefied lportionsare withdrawn from J by line 13 andconducted back into the 'spray chamber S wherein the liquefied portionsundergo self-evaporation and act to cool the incoming precooled raw gasto a liquefying temperature. The residual gas 1s passed from J by linel() back to line 9 and isconducted out of the system.

.ln the first precooler E, a cooling medium which does not freeze abovea temperature ol' about (lo l". must be used. l have found calciumchloride solutions particularly adapted t'or my purpose although I donot wish to berestricted solely to the use of that cooling medium sinceit is obvious that many other cooling mediums may be suitable. In theprecooler H', 1 advantageously use gasoline and the temperature in theprecooler H varies between the temperature of the incoming raw gasthrough line 3 and the temperature of the incoming cold gas through line7. It is necessary that a cooling medium in H-be one which stands a verylow temperature, say down to -70 F. or lower and at the same time doesnot vola`l tilize to an appreciable degree. I prefer not to usecalcium-chloride solution in thesecond precooleLH because calciumchloride solution ordinarily cannot standv the extremely lowltemperatures --which are foundin the second precooler. Gasoline couldnot he used as a cooling medium in the first prethe desired liquefiedcooler because too much of the gasoline would be volatilized at themaintained therein.

It will be seen that the process is a cyclic one, raw gas being cooled,,parts thereof liquefied, and the residual cold gas used to cool theliquid 4cooling medium with which the raw gas is precooled. By utilizingthe cold lean gasto maintain the cooling medium at an eifectivetemperature and then bringing the raw gas into actual intimate contactwith thesaid cooling medium, I obtain an almost theoretically efficientexchange of heat. What I claim is 1..In the recovery of gasoline by therefrigeration of natural or casinghead gas the step which comprisescontaetingthe vapors of gas to be cooled with a solution of a coolingmedium cooled by cold gas subsequently obtained from the natural gas'in. a later stage ofthe operation.

.v 2. The process of. recovering gasoline from natural gasbyrefrigeration, which process comprlses` passing the gas in acouutercurrent relation to a downward flow of a cooling medium wherebythe gas is precooled to a temperature between 0 F. and F., passing thegas in contact with a downward flow of a second cooling medium wherebythe gas further cooled, passing the gas into intimate contact with lowerboiling liquid' undergoing self-evaporation, separating and withdrawing'condensed -liquid from the resulting gaseous mixture` passing theresidual gas luto countercurrent contact with the second coolin mediumwhereby the vsame is cooled, su sequently passing the residual gas intocontact with `the first cooling medium whereby the sam is cooled,liquefying at least a part of the! residual gas and conducting saidliquefied portions into the system and into contact with the precooledraw gas, permitting the liquefied portion lo undergo self-evaporw,

tion whereby the raw gas-is chilled to a liquefying temperature and thenseparating constituents from the gas.

In "testimony whereof, I have hereunto atixcd my signature.

FRED E. IIOSMER.

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